1. Technical Field
The present disclosure is directed to a braking system for a wheelchair, and more particularly, to a braking system for a wheelchair which prevents rearward movement of the wheelchair when there is no wheelchair occupant and includes anti-tip capability.
2. Background of the Related Art
Wheelchairs have become very common and indispensable instruments. Brakes or anti-tipping structures on the wheelchairs, which prevent movement of the wheelchairs in all directions are known. Such brakes or anti-tipping structures typically include a locking mechanism that engages various parts of the wheelchair. Various types of improved brake systems have been developed.
For example, U.S. Pat. No. 4,565,385 to Morford is directed to a tiltable supporting wheelchair mechanism mounted on a conventional wheelchair, comprising a tilting mechanism for controlled raising of the front of the wheelchair above a floor, a leg support means for selectively supporting an occupant""s leg, and a head rest means mounted to the wheelchair.
U.S. Pat. No. 5,137,295 to Peek is directed to a wheelchair having an active anti-tipping assembly to prevent its rider from tipping over backwards when a backrest frame is reclined rearwardly. The anti-tipping assembly has a pair of laterally spaced linkage members whose top ends are pivotally connected to the backrest frame. The bottom ends of the linkage members are pivotally connected to leg members at a point intermediate to their length. The leg members in turn have their top ends pivotally connected to the rear ends of the longitudinally extending bottom frame members of the wheelchair frame. The linkage members are adjustable in length. The anti-tipping leg members have rollers secured to their rearward ends.
U.S. Pat. No. 5,203,433 to Dugas is directed to a wheelchair having an automatic braking assembly which automatically locks one or both wheels of the wheelchair when a patient attempts to rise. The automatic braking assembly includes a movable seat, a locking bar connected to a locking member rigidly connected to a hub of the wheel which is received in the cavity of the locking bar to selectively lock the hub and wheel in a stationary position.
U.S. Patent No. 6,092,824 to Ritchie et al. discloses a wheelchair anti-rollback assembly which prevents the wheelchair from rolling backwards and away from its occupant as the occupant attempts to mount or dismount the wheelchair. The wheelchair includes a braking member that engages the drive wheels to prevent rearward movement of the wheelchair when the seat is not occupied.
Even though these devices may be suitable for the specific individual purposes for which they are designed, a need exists for a brake system which is mounted on a conventional wheelchair, and which may engage the ground to prevent rearward movement of the wheelchair, and which may be disengaged without requiring the occupant to separately operate the braking system.
An object of the present invention is to provide a novel type of braking and anti-tip assembly which is simple, convenient, economical and easily adaptable to a conventional wheelchair.
The braking and anti-tip assembly has a pivotable member which is pivotably supported between portions of the wheelchair frame assembly, a pair of arms each of which is fastened to the pivotable member, a pair of stops each of which is fastened to each lower end portion of the arms, an abutment member which is supported on upper ends of arms beneath the wheelchair seat, and a biasing member which is positioned to pivot the pivotable member in a direction to urge the abutment member upwardly into the underside of the seat of the wheelchair and urge the pair of stops downwardly onto the surface on which the wheelchair is supported. The stops are preferably formed of a non-slip material, such as rubber. The shape of the abutment member can be rectangular, circular, square etc., and the abutment preferably has padding positioned about the upper ends of the arms. The biasing member may comprise a coil spring, a torsion spring, or other devices well known in that art.
In another preferred embodiment of the present invention, the system has an abutment member which is secured to an upper arm beneath the wheelchair seat, a pair of mounting plates which are adapted and configured to be secured to opposite sides of the wheelchair, a pivotable frame member which extends between the mounting plates, an arm connected between the abutment member and the pivotable frame member, two legs which are pivotably mounted between the mounting plates about pivotable shafts, two stops which are fastened to the lower end portions of the legs, and two connectors. The connectors are connected between a first connecting port of the pivotable frame member connected to the arm and a second connecting port of the leg. The connectors are pivotably connected to the first connecting port and pivotably and slidably connected to the legs via elongated slots formed in the second connecting port of the leg. The pivotable frame member consists of three parts linked to each other, and is adjustable in length. The system further comprises a handle lock which can be engaged with the leg for maintaining a movable position of the wheelchair.